The designer was pictured wearing the unisex garment on a recent visit to see the WikiLeaks founder at the Ecuadorian Embassy in London - where he is seeking diplomatic asylum to avoid extradition to Sweden - and has revealed the 'I'm Julian Assange' T-shirt will be sold on her website for £40.
Vivienne wrote on her blog: ''T-shirts for Julian: you can show your support of a real hero by going to viviennewestwood.com. Donations to WikiLeaks have been blocked but 100 per cent of T-shirt profits can help fund their work.''
The 'I'm Julian Assange' Vivienne Westwood T-shirt will go on sale this Saturday (03.11.12).
Vivienne isn't the only high-profile supporter of Assange.
He was recently visited by Lady GaGa, who
is said to have spent five hours with him, emerging at midnight after the two had shared a meal.
Assange is wanted in Sweden to face questioning over a sexual assault investigation.
He has been living in the Ecuadorian Embassy since June 2012.
British officials say he will be arrested if he steps out of the building.